FR2678693A1 - Sliding bearing - Google Patents

Abstract

A sliding element includes a surface layer (4) exhibiting a sliding surface (4a) for an associated element (5). The surface layer (4) includes a metallic crystal belonging to the cubic system with a plane defined by (h00) in the sense of the Miller indices, oriented in the direction of the sliding surface (4a) in order to form the sliding surface (4a). The percentage of surface area A of the plane (h00) in the sliding surface (4a) is within the range A >/= 50 %. The invention applies to plane bearings (smooth bearings), for example to the smooth bearing bushes (brasses, half-shells) for automobile camshafts and crankshafts.

Description

SLIDING RANGE

  This invention relates to a sliding element and more particularly to a sliding element having a surface layer having a

  sliding surface for an associated element.

  Sliding bearings of this type are conventionally known as sliding bearings which are applied to engine parts, for example a camshaft having a surface layer attached around an outer peripheral surface of a portion. , formed as a bearing surface, of a base element and consisting of a metal-deposited layer for the purpose of improving seizure and wear resistance, and a bearing portion of a crankshaft, with an enlarged end of a connecting rod or the like, which comprise

a similar surface layer.

  Under present circumstances, there is a tendency to increase the speed and power of an engine, however, prior art sliding bearings suffer from a problem that they can only show an insufficient characteristic. oil retention and low resistance to galling and wear at their surface layer due to an insufficient initial possibility of conformation With regard also to the question of the adhesion of the surface layer to the based,

  there is one point that needs to be improved.

  An object of the present invention is to provide a sliding element of the type described above in which the surface layer has a sufficient oil retention characteristic and in which the initial possibility of conformation of the surface can be improved by specifying the crystal structure of the metal of the surface layer, thus improving the resistance of the layer

  surface to galling and wear.

  Another object of the present invention is to provide a sliding element of the type described above which is designed so that the peel strength of the surface layer can be increased by

relative to the basic element.

  To achieve the above objects, according to the present invention, there is provided a sliding member having a surface layer having a sliding surface for an associated member, wherein the surface layer has a metallic crital belonging to the cubic system with a plane defined by (h OO) in the sense of the Miller indexes oriented towards the sliding surface to form the sliding surface, and in which the percentage of the planar area A (HOO) in the sliding surface is on the beach A

> 50%.

  If the metallic crystal of the cubic system takes an orientation such that the plane (h OO) appears in the sliding surface, the metal crystal having this orientation is of the columnar type and terminates in a pointed end which is an aggregate of crystal-shaped pyramid

  quadrangular forming the sliding surface.

  If the percentage of the surface area A of the plane (h OO), and therefore that of the crystals in the form of a quadragular pyramid in the sliding surface, is equal to or greater than 50% (A> 50%), the vertices of the quadrangular pyramid-shaped crystals may preferentially wear out to give an improved initial possibility of conformation of the surface layer, and the surface area of the sliding surface may increase thanks to the quadrangular pyramid-shaped crystals, so that the This surface layer has a sufficient oil retention characteristic. This increases the resistance to seizing of the surface layer. However, if the percentage of area A is less than 50% (A <50%), it is not possible to obtain the described effect, which does not translate into a decrease in resistance to

seizing of the surface layer.

  Starting from the idea that the metallic crystal is of the cubic system because of the orientation of the plane (h OO), one can obtain an increased atomic density in the direction of the orientation, so that the surface layer can have increased hardness and oil retention characteristics, which leads to an increase in the

  wear resistance of the surface layer.

  Further, in accordance with the present invention, there is provided a slip member having a surface layer having a sliding surface for an associated member, wherein the surface layer is formed of a crystallite aggregate of a Pb alloy. containing not more than 17% by weight of Sn, and, by application to the surface layer of X-ray diffractometry, if the integrated resistance of crystals with a first orientation, with a plane defined by (h OO) in the sense of the indices Miller, oriented in the direction of the sliding surface, is represented by I (a), if the integrated resistance of the crystals at the second orientation, with planes defined by (111) and (222) in the sense of the directionally oriented Miller indices. of the sliding surface is represented by I (b) and the integrated resistance of the crystals at third orientation, with one face of the crystal other than the (h OO), (111) and (222) planes oriented in the direction of the sliding surface is represented by I (c), we have the following relation: I (c) / SI (abc) o O _ 2

  where I (abc) = I (a) + I (b) + 1 (c), I (b) = 0 inclusive.

  The crystal with a first orientation, with the plane (h OO) oriented towards the sliding surface is a columnar crital and its pointed end is a quadrangular pyramid shaped crystal, and therefore the surface layer has a resistance to galling similar to what is described above. Further, in accordance with the present invention, there is provided a slip member in which a void is formed between adjacent columnar crystals forming the surface layer and opens into the sliding surface to serve as an oil reservoir. With such a configuration, the surface layer has excellent lubricity, which leads to a further improvement of the

  resistance to seizing of the surface layer.

  Further, according to the present invention, there is provided a slip member having a base member and an alloy surface layer formed on the base member and having an associated member slip surface, wherein surface consists of a base layer obtained by precipitation on the base element, and a layer, forming the sliding surface, obtained by precipitation on the base layer, the base layer comprising a dense aggregate of crystals granular, the layer forming the sliding surface having at least one of a plurality of quadrangular pyramid-shaped crystals, or a plurality of truncated quadrangular pyramidal-shaped crystals forming the sliding surface. The aggregate of granular crystals forming the base layer is dense and it follows that the

  base layer adheres strongly to the base element.

  On the other hand, the layer forming the sliding surface has good adhesion to the base layer because it is made of the same material as the base layer. This makes it possible to obtain an improvement in the peel strength of the surface layer compared to to the base element The layer forming the sliding surface has a seizing resistance similar to that described above, since it comprises the crystals in the form of a pyramid

quadrangular and / or analogous.

  Further, according to the present invention, there is provided a sliding member having a base member, and an alloy surface layer formed on the base member and having a sliding surface for an associated member, slip member in a wherein the surface layer is comprised of a precipitated primary layer formed on the base member and a secondary layer precipitated on the primary layer, the primary layer comprising a plurality of columnar crystals extending near each other from the face of the base member, and the secondary layer comprising an aggregate of granular crystals having a hardness less than that of the crystals

of the primary layer.

  With the above configuration, the possibility of initial conformation is improved because of the low hardness of the secondary layer, which allows, at the time of the occurrence of galling, to increase the surface pressure in the initial step In addition, after the initial step of starting the sliding movement, ie after the secondary layer wears out, the wear of the primary layer is substantially eliminated, due to the fact that that the hardness of the primary layer is increased as a result of

the orientation of the plan (h OO).

  The above and other objects, features and advantages of the invention will become apparent in

  considering the description below of achievements

  preferred, taken in conjunction with the accompanying drawings.

  Figure 1 is a perspective view of a camshaft; Fig. 2 is a sectional view illustrating the relationship between a bearing portion of the camshaft and a plain bearing; Figure 3 is a schematic perspective view of an essential portion of a surface layer; Fig. 4 is an illustration for explaining how to measure the tilt angle of a columnar crystal; Fig. 5 is an X-ray diffraction spectrum for a Ni crystal of the surface layer; Fig. 6A is a photomicrograph showing the crystalline structure of Ni in a sliding surface; Figure 6B is a schematic illustration taken from Figure 6A; Fig. 7 is a graph illustrating the relationship between the percentage of area of a plane (h OO) of the sliding surface and the surface pressure of the surface layer when seizure occurs; Fig. 8 is an X-ray diffraction spectrum for a Pb alloy crystal of the surface layer; Fig. 9 is a photomicrograph showing the crystalline structure of a Pb alloy of the slip layer; Fig. 10 is a photomicrograph showing the crystal structure of a Pb alloy, taken in a longitudinal section of the surface layer; FIG. 11 is a graph illustrating the relationship between the area percentage of the plane (h OO) of the sliding surface and the surface pressure

  of the surface layer when seizure occurs.

  Fig. 12 is an exploded plan view of a smooth pad; Fig. 13 is a sectional view taken along line 13-13 of Fig. 12; Figure 14 is a schematic view of an essential portion of the sliding surface; Figure 15 is a schematic longitudinal sectional view of an essential portion of the surface layer; Fig. 16 is a graph illustrating the relationship between Sn content and the level of presence of crystals having the first orientation; Fig. 17 is a photomicrograph showing a crystalline structure of a Pb alloy of the sliding surface; Fig. 18 is a graph illustrating the relationship between the rate of presence of crystals having a first orientation and the surface pressure when seizure occurs; Fig. 19 is a graph illustrating a relationship between Cu content and the level of presence of crystals having a third orientation; Fig. 20 is a graph illustrating a relationship between the rate of presence of the crystals having the third orientation and the surface pressure when seizure occurs; Figure 21 is a schematic longitudinal sectional view of an essential portion of a surface layer; Fig. 22 is a photomicrograph showing a crystalline structure of a Pb alloy of the sliding surface after a wear test; Fig. 23 is a photomicrograph showing a crystalline structure of a Pb alloy of the sliding surface in a comparative example after the wear test; Fig. 24 is an illustration showing, in longitudinal section, an essential portion of a surface layer during the progression of wear; Fig. 25 is a schematic perspective view of an essential portion of the sliding surface; Fig. 26 is a photomicrograph showing the crystal structure of the Pb alloy of the sliding surface; Fig. 27 is an illustration for explaining how to measure the tilt angle of a columnar crystal; Figure 28 is a longitudinal sectional view of the essential portion of the surface section; Fig. 29 is a photomicrograph showing the crystalline structure of a Pb alloy, taken in a longitudinal section of the surface layer; Fig. 30 is a photomicrograph showing a crystalline structure of the Pb alloy in a surface of the basecoat; Fig. 31 is an X-ray diffraction spectrum for a Pb alloy crystal of the base layer; Fig. 32 is an illustration for explaining a peel test for the surface layer; Figure 33 is a schematic longitudinal sectional view of an essential portion of the plain bearing; Fig. 34 is a photomicrograph showing the crystalline structure of the Pb alloy taken in the longitudinal section of the surface layer; and FIG. 35 is a schematic view in longitudinal section of an essential portion of the diaper

of surface.

  Figures 1 to 11 represent a first

  embodiment of the present invention.

  Referring to Figs. 1 and 2, a camshaft 1, slip member for an internal combustion engine, comprises a base material 2 made of cast iron as the base member. A surface layer 4 is attached to an outer peripheral surface of a bearing portion 3 of the base material 2 The surface layer 4 has a sliding surface 4a for a bearing 5 as an element

associated.

  The surface layer 4 is formed by an electroplating process and consists of an aggregate of metal crystals belonging to the cubic system. A face-centered cubic mesh and a centered cubic mesh are included.

in the cubic system.

  Examples of metal crystals having a face-centered cubic mesh are monometallic crystals and alloy crystals such as Pb, Ni, Cu, Al, Ag, Au and the like Examples of metal crystals having a centered cubic mesh are crystals monometallic and alloy crystals such as Fe, Cr, Mo, Tu, Ta,

Zr, Nb, V and the like.

  Predetermined crystals of a metal crystal have a plane defined by (h OO) in the sense of the Miller indices oriented towards a

  sliding surface 4 has to form the latter.

  The percentage of area A of the plane (h OO) in the sliding surface 4 a is located on the beach

At 350%.

  If a characteristic orientation is given to a metallic crystal of a cubic system, so that a plane (h OO) appears on the sliding surface 4a in this way, the metal crystal having this orientation characteristic becomes a columnar crystal 7 extending from the bearing portion 3, and the pointed ends of the columnar crystal 7 become crystals in the form of a quadrangular pyramid 6 forming the sliding surface 4a. Among the columnar crystals 7, some of them extend from the base material 2 but are broken in the middle, and some of them extend from such a broken columnar crystal This is also true for the

  columnar crystal that will be described below.

  If the percentage of area A of the plane (h OO) and thus quadrangular pyramid shaped crystals 6 is in the range A> 50%, as described above, the peaks with quadrangular pyramid shaped crystals can preferentially wear to improve the possibility of initial conformation of the surface layer 4 and the area of the sliding surface 4a can increase thanks to the crystals in the form of the quadrangular pyramid 6, so that the surface layer 4 has a sufficient oil retention characteristic. This improves the

  resistance to seizing of the surface layer 4.

  However, if the percentage of area A is less than 50% (A 50%), it is not possible to obtain this effect, which results in a reduction in the resistance to galling of the layer.

surface 4.

  In addition, since the metallic crystal belongs to the cubic system because of the orientation of the plane (h OO), we obtain an increase in the

  atomic density in the direction of orientation.

  As a result, the surface layer 4 has increased hardness, and the surface layer 4 can be given the oil retention characteristic, thereby providing improved wear resistance.

of the surface layer 4.

  To obtain an excellent sliding characteristic as described above, the inclination

  Columnar crystals become important.

  If a plane B, in dashed line, along the sliding surface 4a is defined below, on the side of its base surface, as shown in FIGS. 3 and 4, and if O is denoted by the angle d inclination defined between a line a 3 passing through the apex a 1 and the center a 2 of the base surface of the quadrangular pyramid shaped tip 6 and the reference line a 4 passing through the center a 2 of the surface perpendicular to the plane B in mixed lines, the angle of inclination O of the columnar crystal 7 is in the range OO ac 30 If the angle of inclination 9 is greater than 30 (9> 300), the characteristic oil retention of the surface layer 4 and the preferential wear of the apex are reduced which results in reduced resistances to the

  wear galling for the surface layer 4.

  Concrete examples will be described below.

  The outer peripheral surface of the bearing portion 3 of the cast iron base material 2 has been subjected to an electroplating process to form a surface layer 4 consisting of an aggregate

of Ni crystals.

  The conditions of the electroplating process are as follows: the plating bath used was a mixed bath of nickel sulphate and nickel chloride; the p H of the plating bath was 4.5 or less (constant); the additive was boric acid or an organic additive; the temperature of the plating bath was 50 C; the current density

was 9 A / dm '.

  FIG. 5 is an X-ray diffraction spectrum for a Ni crystal, a spectrum on which a peak b indicates a plane (200) and a peak b 2 indicates a plane (400), both of which these planes belonging to the (h OO) planes It can be seen in FIG. 4 that the Ni crystals are present in the surface layer 4 and are oriented so that the (h OO) plane lies in a plane parallel to the plane in mixed line B extending along the

sliding surface 4 a.

  In this case, the higher the height of the peaks b and b 2, and therefore that of the integrated resistance, the higher the degree of orientation of the Ni crystals increases This results in an increase in the percentage of area A of the plane (h OO) in the sliding surface 4 a The degree of orientation is obtained by varying the conditions of the electroplating process In FIG. 5, the percentage of area A of the plane (h OO) in the sliding surface 4 a is equal to

% (A = 100%).

  Fig. 6A is an electron microphotograph (magnification 5000) showing a Ni crystal structure in the sliding surface 4a, and Fig. 6B is a schematic illustration taken from Fig. 6A. FIG. 6B shows that the sliding surface 4 has crystals in the form of a quadrangular pyramid. The angle of inclination 8 of each

  Columnar crystal is located on the beach O c 9 5 30.

  FIG. 7 illustrates the results of a seizure test for surface layer 4 consisting of a Ni crystal. This test was performed using a disk-tipped test machine, and the test conditions are as follows: the material used for the disc was a material of the nitrided carbon type (material 548 C); the number of revolutions of the disc was 10 m / s; and the oil feed rate was 40 cm 3 / min. In FIG. 7, the seizure resistance was estimated by determining the force exerted on the tip, i.e., a newton (N),

when the seizure occurred.

  As can be seen in FIG. 7, it is possible to improve the resistance to seizing of the surface layer 4 by giving the percentage of area A of the plane (h OO) of the sliding surface 4 to a value of 50 % or more (AQ> 50%) It should be noted that the base material 2 can be made of steel

or an Al alloy.

  The following is an example of a surface layer formed of a Pb alloy and attached to the inner peripheral surface of an internal combustion engine rocker arm in which

  it is necessary to introduce the axis of the rocker arm.

  This inner periphery surface of a base material made of alloy Ai into which a rocker shaft is to be inserted has been subjected to an electroplating process to form a surface layer consisting of an aggregate of crystals.

of Pb alloy.

  The conditions of the electroplating process were as follows: the plating bath was a borofluoride plating bath containing 100 g / liter of Pb 2 and 10 g / liter of Sn 2 the additive was borofluoric acid or a organic acid; the temperature of the plating bath was 250 C; the

  Cathode current density was 8 A / dm 2.

  Fig. 8 is an X-ray diffraction pattern for a crystalline structure of the lead alloy in the surface layer, spectrum on which a peak b indicates a plane (200) and a peak b 2 indicates a plane (400 ), one and the other of these planes belonging to the planes (h OO). It can be seen in FIG. 8 that the surface layer consists of the lead alloy crystal oriented so that the plane (h OO) is in a plane parallel to the dashed line B extending along the sliding surface Therefore, in this example, the percentage of the plane area A (h OO) in the sliding surface is

equal to 100% (A = 100%).

  Fig. 9 is an electron microphotograph (10,000 magnification) showing a crystalline structure of the lead alloy of the slip layer and Fig. 10 is an electron microphotograph (magnification 5,000) showing a crystalline structure of the lead alloy. In a longitudinal section of the surface layer. It can be seen in FIGS. 9 and 10 that the surface layer is formed of an aggregate of columnar crystals and that the sliding surface is formed of crystals in the form of a quadrangular pyramid. tilt 9 of each

  Columnar crystal is on the range 00 <e <Q 10 *.

  FIG. 11 illustrates the results of a seizure test for the surface layer consisting of the Pb alloy crystal. This test was performed using a disk-tipped test machine, and the test conditions were the same as those described above for the surface layer

consisting of the Ni crystal.

  As can be seen in FIG. 11, the resistance to seizing of the surface layer can be improved by giving the percentage of area A of the plane (h OO) of the sliding surface a value

  equal to or greater than 50% (A)> 50%).

  The technology disclosed in the first embodiment described above is not only limited to the camshaft and rocker arm described above, but can also be applied to slip elements such as a crankshaft of motor having a surface layer having a metal crystal such as Ni on a bearing portion, and a motor piston provided with a surface layer having a metal crystal such as Fe on a skirt portion, in combination with a piston made of Al alloy and

  a cylinder block made of Al alloy.

  Figures 12 to 20 illustrate a second

  embodiment of the present invention.

  Referring to Figures 12 and 13, a smooth two-piece bearing 8, as a sliding member, is applied to a crankshaft bearing portion of an engine, as well as to an enlarged end of a crankshaft. a rod or the like, and it consists of a first half 81 and a second half 82 The halves 81 and 82 have the same structure and each has a base 9 and a surface layer 11 formed on the base 9 and having a sliding surface 11a for an associated element The base 9 consists of a support 12 and a doubling layer 13 formed on a surface of the support 12 to carry the surface layer 11 The surface layer 11 is formed by a electroplating process Optionally, it is possible to provide a layer consisting of a Cu deposit between the support 12 and the doubling layer 13 and a barrier layer consisting of a Ni deposition between the doubling layer can be provided. 13 and the layer

surface 11, if necessary.

  The support 12 is formed of a rolled steel sheet, and the thickness of the support depends on the determined thickness of the smooth pad 8 The doubling layer 13 is formed of copper, a copper-based alloy, d aluminum, an aluminum-based alloy, etc., and the thickness of the doubling layer 13 is in the range of 50 to 500 μm and normally of the order of 300 μm. The surface layer 11 is formed of an aggregate of Pb alloy crystals and the thickness of the surface layer 11 is in the range of 5 to 50 μm and normally

of the order of 20 μm.

  The lead alloy forming the surface layer 11 contains Sn as an indispensable alloying element and, if necessary, can contain at least one element selected from the group consisting of Cu, Fe, Cr, Co, In, The function of Ag, Ti, Nb, Sb, Ni, Cd, Te, Bi, Mn, Ca and Ba Sn is to increase the resistance of the surface layer 11. Each of Cu, Ni, Mn Fe, Cr and Co has for function

  to increase the hardness of the surface layer 11.

  In addition, each of the elements In, Ag, Tl, Nb, Sb, Cd, Te, Bi, Ca and Ba serves to make the surface layer 11 softer to provide a

  improved possibility of initial conformation.

  The surface layer 11 comprises crystals having a first orientation with a plane defined by (h OO) in the sense of the Miller indices oriented towards the sliding surface 11a to form the sliding surface 11a. The crystals having the first orientation have As a function of improving the sliding characteristic of the surface layer 11 In addition to the crystals having the first orientation, in certain cases the surface layer 11 also comprises crystals having a second orientation with planes defined by (111) and (222) in the sense of the Miller indices oriented in the direction of the sliding surface. In the Pb alloy crystal, the (h OO) plane and the (111) plane (including plane (222)) are in a relationship such that if the area of one of these planes decreases, that of Thus, with the exception of the case where the surface layer 11 consists only of crystals having a first orientation, it is also necessary to take into account the crystals having the first and the second orientation, crystals which

are in mutual relationship.

  From this point of view, the presence rate of the crystals having the first orientation in the surface layer 11 is defined as follows: If the integrated resistance of the crystals having the first orientation with the plane defined by (h OO) in the sense Miller indices oriented in the direction of the sliding surface Ila is represented by I (a) and if the integrated resistance of the crystals having the second orientation with the planes defined by (111) and (222) in the sense of the Miller indices oriented in the direction of the sliding surface 11a is represented by I (b), by applying an X-ray diffraction measurement to the surface layer 11, the following relationship is: 0.5 1 (a) II ( ab) S 1.0 o XI (ab) = I (a) + I (b); I (b) = O is included; and I (a) / P I (ab) represents the presence rate R of

crystals with a first orientation.

  As shown in FIGS. 13 to 15, the first orientation crystal 141 with the plane (h OO) or closed in the direction of the sliding surface is a columnar crystal extending from the liner layer 13, and its end pointed is made of a crystal shaped pyramid

quadrangular 15.

  If the presence rate R 1 of the first orientation crystals 141 is determined as described above, the peaks with quadrangular pyramid-shaped crystals may preferentially be used to improve the possibility of initial conformation of the crystal layer. surface 11 and the area of the sliding surface 11a can increase due to the crystals in the form of quadrangular pyramids 15, so that the surface layer 11 has a sufficient oil retention characteristic This makes it possible to improve the resistance 1. Since the first orientation crystals 141 have a face centered cubic mesh due to the orientation of the (h OO) plane, the atomic density increases in the direction of orientation, so that the surface layer 11 has increased hardness and the surface layer 11 can exhibit the oil retention characteristic, thus ensuring Improvement in the wear resistance of the surface layer 11 In FIGS. 14 and 15, reference numeral 142 represents

  a second orientation crystal that is granular.

  In order to obtain an excellent sliding characteristic as described above, the angle of inclination O of the first orientation crystals 14 is in the range 0a <_e 430 ', as in

  the first realization (see Figures 3 and 4).

  Given the composition of the surface layer 11, the Sn content, which is an indispensable alloying element, influences the presence rate R 1 of the first orientation crystals 14. FIG. 16 illustrates a relationship between the content of Sn and the rate of presence R 1 of the crystals with a first orientation 14 As can be seen on the solid line curve c 1 of FIG. 16, the presence rate R 1 can remain at the value R 1 δ> 0.5, c That is, at a value equal to or greater than 50%. A preferred range of Sn content is from 3% by weight (limit included) to 12% by weight (limit).

included).

  A dashed curve c 2 in FIG. 16 indicates the case where the surface layer comprises crystals having a third orientation which adversely affect the slip characteristic, in addition to crystals 141 and 142 having the first and second orientations. below the crystals having the third orientation and the results indicated by the dashed curve c 2 are obtained by taking for the presence rate R a value equal to or less than 0.2 (R 0.2). Even in this case, the Sn content is defined by the

same way as described above.

  During the formation of the surface layer 11 by the electroplating process, the plating solution used is a borofluoride-based plating solution containing 40 to 180 g / liter of Pb 2, 1.5 to 35 g / liter of Sn 2 and optionally at most g / liter of Cu 2 and an additive The additive that can be used is an organic additive which corresponds to at least one compound selected from the group consisting of a quinone-based compound such as hydroquinone, catechol etc., a compound based on an amino acid such as gelatin, peptide, etc., an aldehyde such as benzaldehyde, vanillin, etc. The amount of organic additive added is in the range of 1.5 at 18 g / liter as the total amount If necessary, borofluoric acid and / or boric acid can be added to the plating solution in order to adjust the resistance of the fluid during stressing. plating solution temperature is in the range of 350 C and the density of c our cathode is

  in the range of 3 to 15 A / dm 2 An example will be described.

  A doubling layer 13 made of a Cu alloy was subjected to an electroplating process to form a surface layer 11 consisting of a

  aggregate of Pb alloy crystals.

  The conditions of the electroplating process were as follows: a plating solution was a boro-fluoride-based plating solution containing 110 g / l Pb + 10 g / l of Sn 2 and 2.5 g / l of Cu 2+; an additive was an organic additive; the temperature of the plating solution was 25 ° C; and the current density was 6 A / dm The composition of the surface layer 11 comprises 90% by weight of Pb, 8% by weight of Sn and

2% by weight of Cu.

  X-ray diffraction was carried out for the surface layer 11 to obtain results similar to those of FIG. 8 Therefore, only the peaks of the planes defined by (200) and (400) in the sense of the Miller indices have been observed on the diffraction spectrum by

  X-rays These two planes belong to the plane (h OO).

  This confirmed that the surface layer 11 was formed only by crystals having a first orientation 14 In this case, the total integrated resistor ú I (ab) is equal to 679,996 (_I (ab) = 679,996), provided that I (b) = 0 and therefore the resistance SI (ab) is equal to the integrated resistance I (a) of the first orientation crystals 141 Therefore, the presence ratio R 1 of the crystals at

  first orientation 141 is 1.0 (R 1 = 1.0).

  The crystalline structure of the Pb alloy of the surface layer 11 was examined by an electron microscope and the result showed that the surface layer 11 has a crystalline structure similar to that of FIGS. 9 and 10. 11 consists of crystals with a first orientation 141 and thus of columnar crystals which are crystals in the form of a quadrangular pyramid forming the sliding surface 11a. The angle of inclination of the crystals with a first orientation

  141 was on the beach of O _e O <1 o O.

  Figure 17 is an electron microphotograph (10,000 magnification) showing a crystalline structure of a lead alloy in another sliding surface 11a. On the surface 17, granular crystals are observed which are crystals 142 having a second orientation, in addition to pyramid-shaped crystals

quadrangular 15.

  In FIG. 17, the integrated resistance I (a) of the first orientation crystals 141 is equal to 37 172 (I (a) = 37 172), and the integrated resistance I (b) of the crystals having the second orientation 142 is equal to 24,781 (I (b) = 24781) Therefore, the presence rate R 1 of the first orientation crystals 141 is 0.6 (R 1 = 0.6) The inclination angle U of the first orientation crystals

  141 is on the beach of O Q <Q, <100.

  FIG. 18 shows the relationship between the presence ratio R 1 of the first orientation crystals 141 and the surface pressure when the seizing appears for the surface layers 11 of different plain bearings 8 In FIG. 18 the curve d1 corresponds to the relationship in the case where the angle of inclination e of crystals with a first orientation 141 is in the range of O <ei 10; the curve d 2 corresponds to the relation in the case where the angle of inclination e of the crystals with a first orientation 141 is in the range 0 Q. <420; and the curve d 3 corresponds to the relation in the case where the angle of inclination 6 of the crystals with a first orientation 141 is in the range

0: 8,130

  The seizure test was carried out by placing each of the plain bearings 9 in sliding contact with a rotating shaft and gradually increasing the load applied to the smooth bearing 8. FIG. 18 shows the surface pressure determined when the seizure appears in the surface layer.

  11 of each of the plain bearings 8.

  The test conditions were as follows: the material used for a rotating shaft was JIS 548 C nitrided material; the number of revolutions of the rotating shaft was 6000 rpm; the feed temperature of Thuile was 1200 C; the supply pressure of the oil was 3 kg / cm 2, and the applied load

was 1 kg / s.

  As can be seen in FIG. 18, the resistance to seizing of the surface layer 11 can be improved by giving the presence ratio R 1 of the crystals with a first orientation 141 a value equal to or greater than 0.5 (R 1 a 0.5) A preferred range of the presence rate R 1 of crystals at first

  orientation 141 is in the range 0.8, R 1 Es 1.0.

  It should be noted that the best resistance to galling

is obtained for R 1 = 1.0.

  In the surface layer 11, crystals having a third orientation, i.e. Pb metal crystals with a crystal face other than the (h OO), (111) and (222) planes oriented in the direction of the sliding surface, may be precipitated in some cases, as described above This crystal face may have the planes (220), (311), (331) and (420) in the sense of the Miller indices. the third orientation adversely affects the seizing resistance of the surface layer 11 and therefore the rate of presence of the crystals having the third orientation must be canceled. Given this, the rate of presence of the crystals having the third orientation in the surface layer 11 is defined as follows. If, when measuring by X-ray diffractometry, the integrated resistance I (a) of crystals having the first orientation 141 with a plane defined by (h OO) in the sense of the Miller indices oriented in the direction of the sliding surface is represented by I (a); if the integrated resistance of the second orientation crystals 142 with (111) and (222) planes in the sense of the Miller indices oriented towards the sliding surface is represented by I (b); and if the integrated resistance of the third orientation crystals 142 with a crystalline face other than the (h OO), (111) and (222) planes in the sense of the Miller indices oriented towards the slippery surface is represented by I (c ), we have the following relation: 1 (c) / ET (abc) 0, 2 ot I (abc) = I (a) + I (b) + I (c); I (b) = O is included; and I (c) / I I (ac) is the R 2 presence rate of

crystals with third orientation.

  With regard to the composition of the surface layer 11, the content of Cu, Ni, Mn, Fe, Cr, Co, Sb, Cd, Bi and Ca, which are selective alloying elements affects the presence rate R 2 crystals

  presenting the third orientation.

  FIG. 19 illustrates the relationship between the Cu content and the presence ratio R 2 of the crystals with a third orientation. As can be seen in FIG. 19, the presence rate R 2 can be maintained at the value of 0.2 or less. by taking a Cu content of at most 5% by weight A preferred range of the Cu content is from 1% by weight (including limit) to 3% by weight (including limit) The content of the other alloying elements Selective such as Ni also presents the same trend as the content

in Cu.

  FIG. 20 shows the relationship between the presence ratio R 2 of the crystals having the third orientation and the surface pressure at the onset of seizure for the surface layer of each of the different smooth pads 8 The composition of the surface layer 11 comprises 90% by weight of Pb, 8% by weight of Sn and 2% by weight of Cu. The curve e 1 in FIG. 20 corresponds to the relationship in the case where the presence rate R 1 of the crystals with a first orientation 141 is 1.0 (R 1 = 1.0) and therefore I (b) = 0, and the surface layer 11 consists of crystals having the first and third orientations. The curve e 2 corresponds to the relationship in the case where the The presence rate R of the first orientation crystals 141 is 0.8 (R 1 = 0.8) and the surface layer 11 is made up of crystals having the first, second and third orientations. the same way and in the

  same conditions as those described above.

  As can be seen in FIG. 20, the resistance to seizing of the surface layer 11 can be improved by giving the presence ratio R 2 of crystals with a third orientation a value equal to or less than 0.2 (R 2 i 6 0.2) The presence rate R 2 of the crystals at third orientation is

  preferably equal to or less than 0.1 (R 2 Xc 0.1).

  It should be noted that R 2 = O corresponds to the case where there are no crystals with a third orientation

in the surface layer 11.

  The optimum state of the surface layer 11 is obtained when the inclination 8 of the first orientation crystals 141 is in the range of Q 0 <e Q 10 and when the presence ratio Ri of the first orientation crystals 141 is a value determined by the following expression: R 1 = I (a) / ZI (ab)) 0.8 For the selective alloying elements described above, it may be taken for the content of Ag, Nb, Te or Ba , a value equal to or less than 10% by weight to avoid a decrease in the resistance

of the surface layer 11.

  If it is desired that the elements In or TI, among the selective alloying elements described above are contained in the surface layer 11, an In coating layer or the like can be formed on a layer obtained by depositing an alloy of Pb and can be subjected to a heat treatment at a temperature of 120 to 200 ° C for 15 to 60 minutes, whereby In or the like diffuses into the layer obtained by Pb alloy deposition for If the content of In or the like is excessive, the surface layer 11 becomes too soft, which results in the decrease of the melting point and, in turn, a decrease in the resistance of the surface layer 11 In addition, there is a risk that the In element or the like may form an intermetallic compound (or compounds) with another element such as Sn, Ni and Fe, so that stratification separation may occur. therefore the content of In or Tl is given after a value ranging from 0.5% by weight (limit included) to 10% by weight (limit included) The adjustment of this content can be carried out by varying the thickness of the layer

coating.

  Figures 21 to 27 represent a third

  embodiment of the present invention.

  As can be clearly seen in FIG. 21, a vacuum 16, serving as an oil reservoir, is defined between the crystals 141, having the first orientation, adjacent, that is to say between the adjacent colormal crystals of the layer It is advantageous for the surface area A 1 occupied by the openings of the voids 16 in the sliding surface to be open to the sliding surface 11a.

  It is in the range 0.2% -5 to 1% to 10%.

  Table 1 illustrates the comparison of the example of the present invention with a comparative example in configuration and characteristics. The surface layer is made of a Pb alloy containing 8% by weight of Sn and 2% by weight of Cu. both in the example of the present invention and in the comparative example. The seizure test was carried out by putting each smooth bearing in sliding contact with a rotating shaft and gradually increasing the load exerted on the bearing 10. The surface pressure indicated in the table was determined when seizing appeared in the layer. of

smooth pad surface.

  The test conditions are as follows: the material used for a rotating shaft was JIS 548 C nitrided material; the number of revolutions of the rotating shaft was 6000 rpm; the oil supply temperature was 1200 C; the feed pressure of the oil was 3 kg / cm 2; and the charge was

1 kg / s.

  A wear test was carried out by putting each smooth bearing in sliding contact with the rotating shaft over a determined sliding distance and with a load exerted on the smooth bearing as a wave-type dynamic load.

  sinusoidal full synchronized with the rotating shaft.

  The test conditions are as follows: the material used for the rotating shaft was JIS 548 C nitrided material; the number of revolutions of the rotating shaft was 3000 rpm; the maximum load exerted was 600 kg / cm 2 (projected area of the pad: width x diameter); the slip distance was 2.5 x 103 km; the supply temperature of the oil was 120 ° C .; and the supply pressure of

the oil was 3 kg / cm 2.

  Figs. 22 and 23 are electron microphotographs (magnification 10,000) showing the crystalline structure of the Pb alloy in the sliding surface after the wear test, Fig. 22 corresponds to the example of the present invention.

  and Fig. 23 corresponds to the comparative example.

  In Figure 22 we can observe many voids

  16 in the example of the present invention.

  TABLE 1 EXAMPLE OF THE INVENTION COMPARATIVE EXAMPLE Shape of Colormular Granular Crystal Orientation Index in Plane (h O) (X) 100 20 Percentage of Area Affected 3.5 4 1 by Openings of Voids (%) Surface Pressure at 410 190 the grip of the grip Eg (Kgl / cm) Value of the wear (UO) 3, 7 6, 8 As seen in Table 1 and Figure 22, in the example of the present invention, a large number of voids 16, serving as oil reservoirs, open in the sliding surface 11a and therefore the surface layer 11 can exhibit excellent lubricity, thereby ensuring improved resistance to galling. can substantially eliminate the wear of the surface layer II through an effect increasing the hardness of the surface layer Il due to the lubricity and orientation index Oe

100% in the plan (h OO).

  As shown in FIG. 24, even in the event of progression of the wear of the surface layer 11, a similar effect is obtained, since the voids 16 open in the sliding surface 11a. However, if the percentage of the area A 1 occupied by the openings of the voids 16 is less than 0.2% (A 1 <0.2%), the

  lubrication of the surface layer 11 is weak.

  Moreover, if A> 10%, the surface layer II

has reduced resistance.

  A sliding characteristic as described above can be obtained even if the pointed end of the first orientation crystals 141 is a truncated quadrangular pyramid-shaped crystal 17. FIG. 26 is an electron microphotograph (10,000 magnification) showing a structure. crystalline alloy of a Pb when a sliding surface 11a is formed of crystals

  17 shaped truncated quadrangular pyramid.

  In this case, at least a portion of the sliding surface 11a is formed by the surfaces of the upper base 17 with truncated quadrangular pyramid shaped crystals 17 and this will ensure that an oil film can be formed between a associated element 10 and the upper base surface 17 has the initial step of starting the sliding movement to provide an improvement of the

  possibility of initial conformation.

  A pad with a portion of the surface layer 11 formed by crystals 14, having a first orientation is part of the present invention. In this case, the percentage of area A 3 of the end faces of the crystals having the first orientation in the sliding surface

  It is located on the beach at 3 to 50%.

  The angle of inclination Q of the first orientation crystals 14 having a truncated quadrangular pyramid shaped crystal 17 is defined as the angle formed between the line a 3, passing through the center 5 of the upper base surface and by the center a 6 of the lower base portion and a reference line a 4 passing through the central portion a 6 of the lower base surface and perpendicular to the dashed line B, as shown in Figure 27 Even in this case , the angle

  slope is located on the beach O '4 e <30.

  Figures 28 to 32 illustrate a fourth

  embodiment of the present invention.

  Fig. 28 is a sectional view of the plain bearing 8 in accordance with this embodiment and similar to that of Fig. 13 Fig. 29 is an electronic microphotograph (magnification 2,000) showing a crystalline Pb alloy structure taken in a longitudinal section The surface layer 11 is made of an alloy of Pb containing 8% by weight of Sn and 2% by weight of Cu and formed on a doubling layer.

13 made of a Cu alloy.

  As can be seen in FIGS. 28 and 29, the surface layer 11 consists of a base layer 18 obtained by precipitation on the doubling layer 13, and of a layer 19 forming a sliding surface and obtained by precipitation on the

base coat 18.

  FIG. 30 is an electron microphotograph (magnification t 0 000) showing a crystal structure of Pb alloy in a surface of the base layer 18. It can be seen in the figure that the base layer 18 has a dense aggregate of granular crystals. In the embodiment shown, the base layer 18 is formed only

granular crystals.

  The layer 19, forming the sliding surface, comprises a plurality of columnar crystals of Pb alloy extending from the base layer 18, that is to say crystals having the first orientation 141. In the embodiment shown, the layer 19 forming the sliding surface is formed only crystals 14, having the first orientation. To form such a surface layer 11, a method is used which consists firstly in precipitating and forming a base layer 18 on a doubling layer 13 by electroplating under the condition of a cathode current density of 2 A / dm 2 , then to precipitate and form a layer 19, forming the sliding surface, on the base layer 18 by electroplating under the condition of a

  cathode current density of 8 A / dm 2.

  The aggregate of granular crystals forming the base layer 18 is dense because of the low density of the cathode current during its precipitation. As a result, the base layer 18 adheres firmly to the doubling layer 13. layer 19, forming the sliding surface, adheres well to the base layer 18 because it is made of the same material as the base layer 18 This leads to an increased peel strength of the surface layer 11 with respect to the layer

dubbing 13.

  The layer 19, forming the sliding surface, has a sufficient oil retention characteristic and will show a good possibility of initial conformation by preferential wear of the vertices at 1; because it contains the crystals 15 in

quadrangular pyramid shape.

  X-ray diffraction was performed for the slip surface layer 19 to obtain a similar result to that shown in FIG. 8. Therefore, on the X-ray diffraction spectrum, it was observed that diffraction peaks corresponding to the planes (200)

  and (400) in the sense of the Miller indices.

  Here, if the orientation index Oe, as an indicative index of a crystal face orientation characteristic, is defined as follows: Oe = Ihkl / Z Ihkl x 100 (%) o hkl is a Miller's index; Ihkl is a built-in resistance of a plane (hkl); and Z Ihkl is is a sum of Ihkl; closer to 100% is the orientation Oe in a certain plane (hkl), more important is the amount of crystal faces oriented in the direction perpendicular to the plane (hkl). The integrated resistance Ihk1 and the orientation index Oe in the planes (200) and (400) of the Pb alloy crystal are as indicated in FIG.

table 2.

Table 2

  hkl integrated resistance lEhkl orientation index Oe (%)

631,414 92.9

400 44 582 7, 1

  As seen in Table 2, the orientation index Oe in a plane (h OO) of the Pb alloy crystal is 100% and therefore the Pb alloy crystal has its crystal face oriented in each direction of the crystallographic axes

  a, b and c, that is to say according to a plane (h OO).

  If the crystal face is oriented in the direction perpendicular to the (h OO) plane in this way, the atomic density in the direction of orientation is high, since the crystalline structure of the Pb alloy is a cubic face structure As a result, the layer 19, forming the sliding surface, has an increased hardness to show improved strength.

seizing and wear.

  Fig. 31 is an X-ray diffraction spectrum for the Pb alloy crystal in base layer 18. Fig. 31

  no orientation of a particular crystal face.

  The integrated resistances and orientation indices in the different planes defined by (hkl) are

as shown in Table 3.

Table 3

  hkl Integrated resistance lhkl Indiex dlorientatinn Oe (O

111 31 987 42, 1

200 15548 20.5

220 7,233 9.5.

311 9 609 12.7

222 3 730 4.9

400 2,083 2.7

331 3,038.0

420 2 723 3.6

  As seen in Figures 30 and 31 and in Table 3, the Pb alloy crystal shape in base layer 18 is an irregular shape

  with the faces of the crystal oriented randomly.

Table 4 illustrates the comparison of the example of the present invention with a comparative example.

  (1) resistance of the surface layer to peeling.

  In Comparative Example (1), the surface layer is formed of an aggregate of columnar crystals of a Pb alloy, as well as the layer 19 forming the sliding surface in the example of the present invention.

invention.

  The peel strength was estimated by measuring the peel distance. The measurement of the peel distance was made by: cutting transversely in the surface layer 11; heat the resulting surface layer II at 180 ° C for 6 hours and then cool; repeat the cycle with the above steps five times; and subjecting the surface layer 11 to ultrasonic cavitation. When a portion f 2, surrounded by the cut fi, has been peeled in the surface layer 11 to separate it from the doubling layer 13, the distance between the cut f 1 and the portion remained adherent f 3 and the maximum distance was determined as peel distance f 4.

Table 4

  Distance of p 1 a & m in -boiphde Mmrrqr p = (It) Example of the present invention 3 Comparative Example (1) As can be seen in Table 4, with the example of the present invention, it is possible to increase the resistance of the surface layer it peel thanks to the presence of the base layer 18 formed of

  the aggregate of columnar crystals.

  Table 5 illustrates a result of a galling test for the example of the present invention and for a comparative example (2) corresponding to the prior art. In Comparative Example (2), the shape of the alloy crystal of Pb in the surface layer is an irregular shape with randomly oriented crystal faces, as in the layer

  base 18 of the example of the present invention.

  The seizure test was carried out by placing each of the plain bearings in sliding contact with a rotating shaft and gradually increasing the load exerted on the smooth bearing. The table illustrates the surface pressure determined when the seizure appears in the surface layer.

smooth pad.

  The test conditions are as follows: the material used for a rotating shaft was JIS 548 C nitrided material; the number of revolutions of the rotating arb was 6000 rpm; the oil supply temperature was 1200 C; the feed pressure of the oil was 3 kg / cm 2; and the applied load

was 1 kg / s.

Table 5

  Surface pressure of the surface layer at the onset of seizure (kg / cm) Example of the present invention Comparative Example (g) 190 As seen in Fig. 5, the example of the present invention shows excellent resistance to seizure in comparison with comparative example (2) The reason for obtaining such an effect is that the apex has quadrangular pyramid shaped crystals 15 forming the sliding surface 11a may preferentially wear to give improvement of the possibility of initial conformation of the surface layer 11, and that the area of the sliding surface 11a increases due to the quadrangular pyramid shaped crystals 15, so that the surface layer has a retention characteristic of sufficient oil In this case, if the preferential wear of the aperture ai is completed at an initial stage of the start of the sliding movement to form a flat surface (which horn corresponds to an upper base surface of truncated quadrangular pyramid), an oil film is always present between this plane surface and an associated element and consequently the subsequent wear of the sliding surface 11

  will progress extremely slowly.

  A sliding characteristic similar to that described in the previous embodiments can be obtained, even though a plurality of crystals having the first orientation 141 of the sliding surface layer 19 consisting of the Pb alloy contains only crystals. in the form of truncated quadrangular pyramids, as shown in FIGS. 25 and 27, or even if these crystals having the first orientation 141 constitute a combination of crystals 17 and

  crystals in the form of quadrangular pyramids 15.

  A pad 10 with a sliding surface portion 11a formed by quadrangular pyramid-shaped crystals 15 or truncated quadrangular pyramid shaped crystals 17 also forms part of the present invention. In this case, the percentage of area A 2 of the Quadrangular pyramid-shaped crystals 15 and / or the like in the sliding surface 11a is in the range 50%. The angle of inclination of the quadrangular pyramid shaped crystals and truncated quadrangular pyramidal crystals is on the beach 0 e 43 QO as in the

  previously described achievements.

  Figures 33 to 35 illustrate a fifth

  embodiment of the present invention.

  Fig. 33 is a sectional view of a smooth pad of this fifth embodiment and is similar to Fig. 13 Fig. 34 is an electron photomicrograph (magnification 1,500) showing a crystal structure of Pb alloy in a cup. FIG. 35 is a schematic longitudinal sectional view of an essential portion of the surface layer 11 shown in FIG. 34. The surface layer 11 is made of a lead alloy containing 8% of the surface layer 11. by weight of Sn and 2% by weight of Cu and formed on the alloying layer 13 of alloy

of Cu.

  As can be seen in FIGS. 34 and 35, the surface layer 11 consists of a primer layer 20 obtained by precipitation and formed on the doubling layer 13, and a secondary layer 21 obtained by precipitation and formed on the layer

primary 20.

  The primary layer 20 comprises a plurality of columnar crystals of Pb alloy extending in proximity to each other from the doubling layer 13, namely, crystals having the first orientation 141. In the embodiment shown, the primary layer 20 is formed only

  crystals having the first orientation 141.

  A void 16 is formed between the adjacent crystals having the first orientation 141 and it opens in the sliding surface 11a to serve as an oil reservoir. It is interesting that the percentage of surface A 1 occupied by the openings of the voids 16 in a cross section parallel to the sliding surface 11a is

on the beach 0.2% o A 1, 10%.

  The crystalline structure of the Pb alloy in a surface of the secondary layer 21, ie, in the sliding surface 11a, is similar to that shown in Figure 30. Therefore, the second layer 21 has a crystal aggregate. In the embodiment shown, the secondary layer 21 is not formed

than granular crystals.

  To form such a surface layer 11, a method is used which consists in precipitating and forming a primer layer 20 on a doubling layer 19 by an electroplating process under the condition of an 8 A cathode current density / dm 2 and to precipitate and form a secondary layer 31 on the primary layer by an electroplating process under the condition of a cathode current density of 2 A / dm 2 In this case, the surface of the primary layer 20 is formed of crystals in the form of quadrangular pyramids 15 so that the surface of the primary layer 20 has an anchoring effect for the secondary layer 21, thus ensuring good adhesion of the layer

  secondary 21 on the primary layer 20.

  X-ray diffraction was carried out for the primer layer 20 and a similar result to that shown in FIG. 8 was obtained. On the X-ray diffraction spectrum, diffraction peaks were only observed for the

  planes (200) and (400) in the sense of the Miller indices.

  Therefore the orientation index Oe of the crystal

  Pb alloy in the plane (h OO) is similarly 100%.

  If the crystal face is oriented in a direction perpendicular to the (h OO) plane in this way, an increased atomic density is obtained in the direction of orientation because the structure of the Pb alloy crystal is a mesh face-centered cubic, so that the primary layer has an increased hardness, leading to an improvement in its resistance to galling and wear The hardness Hmv of the primary layer 20 is

located on the beach from 20 to 25.

  X-ray diffraction was carried out for the secondary layer 21 to obtain a result similar to that shown in FIG. 31. Consequently, the shape of the crystal of the Pb alloy of the secondary layer 21 is an irregular shape with the As a result, the hardness of the Pb alloy is lower than that of the Pb alloy with its orientation in the plane (h OO). Hardness of the crystal faces randomly oriented in the same way as described above. Hmv of the layer

  Secondary 21 is on the beach from 10 to 15.

  Table 6 illustrates the comparison of an example of the present invention with a comparative example in configuration and performance of the surface layer. The composition of the surface layer is the same both in the example of the present invention.

  invention and in the comparative example.

  The seizure test was conducted by bringing each of the plain bearings into a rotating shaft and gradually increasing the load applied to the smooth bearing. The surface pressure indicated in Table 8 was determined when the seizure occurred.

appeared.

  The test conditions are as follows: the material used for the rotating shaft was JIS 548 C nitrided material; the number of revolutions of the rotating shaft was 6000 rpm; the supply temperature of the oil was 120 ° C .; the oil supply pressure was 3 kg / cm 2; and the applied load was

1 kg / s.

  A wear test was carried out by putting each smooth bearing in sliding contact with the rotating shaft over a given sliding distance and with a load applied to the smooth bearing as a dynamic load of a wave type.

  sinusoidal full synchronized with the rotating shaft.

  The test conditions are as follows: the material used for the rotating shaft was JIS 548 C nitrided material; the number of revolutions of the rotating shaft was 3000 rpm; the maximum load applied was 600 kg / cm 2 (projected area of the pad: width x diameter); the slip distance was 2.5 x 103 km; the supply temperature of the oil was 120 ° C .; and the supply pressure of

the oil was 3 kg / cm 2.

  The crystalline structure of the Pb alloy in the sliding surface after the wear test is similar to that shown in FIGS. 22 and 23. In the primary layer 20 of the example of the present invention, numerous

empty 16.

Table 6

  EXAMPLE OF THE INVENTION COMPARATIVE EXAMPLE Layer Secondary p 1 -rimary layer Granular Granular Granular Column Form Orientation in 100 23 28 (h O 0) Plan (%) Duret 6 (R Ov) 21 14 17 Percentage of area35 4 vacuum opening (%) Surface pressure at 220 200 the occurrence of seizure at the initial stage of demampling 2 of the sliding motion (kg / cm) Value of wear after flow4 6 8 of the initial stage of Sliding Movement (U) Delay As seen in Table 6, the possibility of initial conformation in the example of the present invention is good because of the low hardness of the secondary layer 21, which ensures that the pressure The surface area at the time of occurrence of jamming at the initial stage of the start of the sliding movement can increase, compared with the comparative example. Furthermore, after the initial step of starting the sliding movement has been completed, that is to say after s the wear of the secondary layer 21, the primary layer 20 shows excellent lubricity because a large number of voids 16 open in the sliding surface 11a to serve as oil tanks, as in the smooth pad in addition, the hardness of the primary layer 20 increases because of the orientation index Oe of 100% in the (h OO) plane, so that the wear of the primary layer 20 can be substantially eliminated. if the percentage of area A 1 occupied by the openings of the voids 16 is less than 0.2% (A 1 <0.2%), the power

  lubricant of the primary layer 20 is weak.

  On the other hand, if A 1> 10% the primary layer 20

has reduced resistance.

  The vertices 1 of the quadrangular pyramid-shaped crystals 15 of the primary layer 20 are preferably used at the initial stage of the start of the sliding movement and consequently the possibility of conformation of the primary layer.

20 is good.

  The crystals 141, having the first orientation, in the primary layer 20 may have a shape similar to that shown in the figures and a smooth pad with crystals 141 having the first orientation and forming a portion of the primary layer 20 is also included In this case, the percentage of area A 3 of the end faces of the crystals 14, having the first orientation, in a cross section parallel to the sliding surface, is in the range A 50% 50%. angle of inclination e of the crystals 14, having the first orientation is in the range O 6 <30 as in the

  description previously described In addition, a

  pad 10 with a non-void primer layer 20 also forms part of the present invention. Although the surface layer has been formed by the electroplating process in the previously described embodiments, it should be understood that any other method including those using a gaseous phase, such as gaseous phase by physical process, ionic plating, chemical phase deposition by chemical process, spraying etc. The technology described in the embodiments, from the second to the fifth, is not limited to the smooth pad, but can also be applied

  to other sliding elements.

Claims (10)

  Sliding element comprising a surface layer (4) having a sliding surface (4 a) for an associated element (5), characterized in that said surface layer (4) has a metal crystal belonging to the cubic system with a plane defined by (h OO) in the sense of the Miller indices oriented towards said sliding surface (4 a) to form said sliding surface, and by the fact that the percentage of area A of said plane (h OO) in said surface   slip (4 a) is in the range A> 50%.   2 sliding element according to claim 1, characterized in that said metal crystal is a Pb alloy crystal containing at most 17% by weight of Sn, said surface layer (11) being formed by a crystal aggregate of Pb alloy, and in that, by applying X-ray diffractometry for said surface layer (11), if the integrated resistance of the crystals (141) exhibiting the first orientation with the plane defined by (h OO ) in the sense of the Miller indexes oriented towards the sliding surface (11a) is represented by I (a), and if the integrated surface of the crystals (142 having the second orientation with the planes defined by (111) and (222) ) in the sense of the Miller indexes in the direction of the sliding surface (11a) is represented by I (b), we have the following relationship: 0.5 due I (a) / XI (ab) <-1.0   o EI (ab) = I (a) + I (b), and I (b) = O is included.   Gliding element according to claim 1, characterized in that said metal crystal is a Pb alloy crystal containing 5% or less by weight of at least one of the elements selected from the group consisting of Cu , Ni, Fe, Cr, Mn, Co, Sb, Cd, Bi and Ca, said surface layer (11) being formed by an aggregate of Pb alloy crystals and in that, by application of the diffractometry by the X-rays for said surface layer (11), if the integrated resistance of the crystals (141) exhibiting the first orientation with the plane defined by (h OO) in the direction of the Miller indices oriented in the direction of the sliding surface (11). a) is represented by I (a); if the integrated resistance of the crystals (142) exhibiting the second orientation with the planes defined by (111) and (222) in the sense of the Miller indices oriented in the direction of the sliding surface (11a) is represented by I (b) ; and if the integrated resistance of the crystals (142) having the third orientation with the planes of a crystalline face other than the (h OO), (lil) and (222) planes oriented towards the sliding surface (11 a) is represented by I (c), we have the following relation: I (c) / EI (abc) Z 0.2 o LI (abc) = 1 (a) + I (b) + I (c), and I (b) O is included. 4 sliding element according to claim 2 or 3, characterized in that said surface layer (11) is formed on a base member (9) and in that said crystals (141) having the first orientation are crystals columns extending proximate to each other from the face of said base member (9), voids (16) being formed between adjacent columnar crystals and opening into the sliding surface   (11) to serve as an oil reservoir.   Sliding element according to claim 1, characterized in that said surface layer (11) is formed on a base element (9) and consists of a base layer (18) obtained by precipitation on said a base member (9) and a layer (19) forming the sliding surface, made of the same material as the base layer (18) and precipitated on said base layer, said base layer (18) including a dense aggregate of granular crystals, said layer (19) forming the sliding surface including at least either crystals (15) in the form of a quadrangular pyramid or crystals (17) in the form of quadrangular pyramids truncated under said metallic crystal.   Slide element according to claim 1, characterized in that said surface layer (11) is formed on a base element (9) and consists of a primary layer (18) obtained by precipitation on said a base member (9) and a secondary layer (19) precipitated on said primary layer (18), said primary layer (18) including a plurality of columnar crystals extending in proximity to each other from the face of said base member (9) under said metallic crystal, and said secondary layer (19) including an aggregate of granular crystals having a hardness less than that of said primary layer (18).   Sliding element according to Claim 6, characterized in that voids (16) are formed between the adjacent columnar crystals and open in the sliding surface (11a) for serve as an oil reservoir.   Sliding element comprising a surface layer (11) having a sliding surface (11a) for an associated element (10), characterized in that said surface layer (11) is formed of a crystal aggregate Pb alloy containing not more than 17 wt.% of Sn and that, by application of X-ray diffractometry for the surface layer, if the integrated resistance of the crystals (141) exhibiting the first orientation with a plane defined by h OO) in the sense of the Miller indices oriented towards the sliding surface (11a) is represented by I (a) and if the integrated resistance of the crystals (142) having the second orientation with the planes defined by (111) and (222) in the meaning of the Miller indices oriented in the direction of the sliding surface (Ia) is represented by I (b), there is the following relation: 0.5 ES I (a) / YI (ab) <1, 0   oỷ-I (ab) = I (a) + I (b), and I (b) = O is included.   Sliding element comprising a surface layer (11) having a sliding surface (IX) for an associated element (10), characterized in that said surface layer (11) consists of a crystal aggregate of an alloy of Pb containing 5% or less by weight of at least one element selected from the group consisting of Cu, Ni, Fe, Cr, Mn, Co, Sb, Cd, Bi and Ca and in that applying X-ray diffractometry for said surface layer, if the integrated surface of the crystals (141) exhibiting the first orientation with the plane defined by (h OO) in the sense of the Miller indexes pointing towards the sliding surface (IIa) is represented by I (a); if the integrated resistance of the crystals (142) having the second orientation with the planes defined by (111) and (222) in the sense of the Miller indices oriented in the direction of the sliding surface (illa) is represented by I (b); and if the integrated resistance of the crystals (142) having the third orientation with crystal face planes other than the (h OO), (111) and (222) planes oriented in the direction of the sliding surface (1 ia) is represented by I (c), we have the following relation: I (c) / I (abc) 0.2 o I (abc) = I (a) + I (b) + I (c), and I (b) = O is included. Sliding element comprising a base element (9) and a surface layer (11) made of an alloy formed on the base element (9) and having a sliding surface (11 a) for an associated element ( 10), characterized in that said surface layer (11) includes a plurality of columnar crystals extending in proximity to each other from the face of said base member (9) and in that voids (16) are formed between the adjacent columnar crystals and open into the sliding surface (11a) to serve as a oil tank.   Sliding element comprising a base element (9) and a surface layer (11) of an alloy formed on the base element (9) and having a sliding surface (11 a) for an associated element (10). ), characterized in that said surface layer (11) consists of a base layer (18) obtained by precipitation on said base member (9), and a layer (19), forming a sliding surface and precipitated on said base layer (18), said base layer (18) including a dense aggregate of granular crystals, said slip surface layer (19) including at least one of a plurality of shaped crystals (15) quadrangular pyramid, or a plurality of crystals (16) shaped truncated quadrangular pyramid forming said sliding surface.  Sliding element comprising a base element (9) and a surface layer (11) of an alloy formed on the base element (9) and having a sliding surface (11a) for an associated element (10) , characterized in that said surface layer (11) consists of a primary layer (20) obtained by precipitation on said base element (9) and a secondary layer (21) obtained by precipitation on said primary layer (20), said primary layer (20) including a plurality of columnar crystals extending in proximity to each other from the face of said base member (9) and said secondary layer (21) including an aggregate of crystals granular having a hardness   less than that of said primary layer (20).   Sliding member comprising a base member (9) and a surface layer (11) of an alloy formed on the base member (9) and having a sliding surface (11a) for an associated member (10) , characterized in that said surface layer (11) consists of a primary layer (20) obtained by precipitation on said base element (9), and a secondary layer (21) obtained by precipitation on said layer primary (9), said primary layer (20) including a plurality of columnar crystals extending proximate to each other from the face of said base member (9), the voids (16) being formed between the crystals adjacent columns and opening in the sliding surface (11a) to serve as an oil reservoir, and said secondary layer (21) including an aggregate of granular crystals having a hardness   less than that of said primary layer (20).